Solar heat collectors utilizing hollow pipes or tubes that carry fluid for heat absorption and transfer are well known in the art. They generally include a frame wherein a plurality of tubes or pipes are arranged in a predetermined pattern and connected to a fluid input for receiving such fluid. The solar heat accumulates on the upper surface of the collector. The medium, which is air, within the collector transfers the heat from the upper surface to outer surfaces of such pipes or tubes.
As the fluid flows trough the pipes or tubes it absorbs the heat from their surfaces and exists through a fluid output connection to a point of use. The fluid transfers the absorbed heat at such point of use and returns to the solar heat collector to repeat the absorption and transfer cycle.
To facilitate the solar heat collection, a selective absorption film, generally referred to as a black body, is applied to the upper surface of the collector.
The main disadvantage of the presently used solar heat collectors is the air medium that fills the space between the outer surfaces of such pipes or tubes and the selective absorption film. As it is well known, the air medium is characterized by a low thermal conductivity and high resistance to heat therefore reducing the efficiency of the heat transfer process from the black body to the heating fluid.
Therefore, there is a need for an improved solar heat collector which economically improves heat transfer efficiency of the solar collector.